Method, device and storage medium for fine characterization of directional borehole stress direction

Abstract

The present application relates to the technical field of geological exploration, in particular to a method and device for fine delineation of directional drilling ground stress direction and a storage medium, comprising: obtaining the top angle, azimuth angle and tool face angle of a directional core sample in a target area, obtaining the ground stress direction in the directional core sample, taking the drilling position as the spatial coordinate origin, calculating the spatial positions of the upper and lower ends of the directional core sample, and combining the stratum composition and strike information to perform spatial modeling to obtain a stratum structure model; determining the next drilling direction and position based on the included angle of the upper and lower end faces, selecting three drilling positions that are farthest from each other and have the closest upper and lower end faces of the target layer sample to form a target area, and obtaining the regional stratum strike and ground stress direction through inversion. The present application not only realizes the visualization of the stratum structure, but also effectively avoids the geological risk of blind excavation of the project, and significantly improves the deep exploration accuracy.

Description

Technical Field

[0001] This invention relates to the field of geological exploration technology, and more specifically, to a method, equipment, and storage medium for fine characterization of the geostress direction in directional drilling. Background Technology

[0002] In geological exploration and underground engineering construction, ultra-deep core drilling is the most direct and effective means of obtaining information on the lithology, structure, and stress state of deep strata. As underground space development extends to greater depths, the requirements for the accuracy of in-situ geological characterization are increasing. Wireline coring technology is widely used due to its high efficiency. Obtaining stratum attitude and physical parameters through drilling-while-measuring is crucial for inverting regional geological structural evolution and guiding engineering site selection. Currently, in existing deep geological exploration core drilling operations, on the one hand, the complex geological environment within ultra-deep boreholes makes it difficult to achieve accurate three-dimensional spatial repositioning after core extraction using traditional methods, resulting in significant loss of information on the original stratum strike and stress direction. On the other hand, current operations lack effective simulation and modeling capabilities for the spatial attitude of the core, making it impossible to accurately characterize potential slip surfaces and transform scattered coordinate parameters into a visualized three-dimensional geomechanical model. This not only leads to large errors in the inverted in-situ stress field distribution but also easily results in misjudgments of stratum stability, potentially causing major engineering disasters such as collapses or water inrushes, greatly increasing construction risks and exploration costs. Summary of the Invention

[0003] The purpose of this invention is to provide a method, equipment, and storage medium for fine characterization of the geostress direction in directional drilling. It accurately restores the original underground occurrence through core attitude simulation and inverts the real geostress direction by combining three-dimensional modeling. This not only realizes the visualization of the stratigraphic structure but also effectively avoids the geological risks of blind drilling in engineering and significantly improves the accuracy of deep exploration.

[0004] This invention is achieved through the following technical solution: A method for fine characterization of the direction of in-situ stress in directional drilling includes: In the target area, select a section of borehole to drill and obtain directional core samples. Based on the inertial navigation and tilt measurement of the drilling gyroscope and the flexible characterization and calibration of the inner tube retainer, obtain the apex angle, azimuth angle and tool face angle of the directional core samples. Based on the apex angle, azimuth angle, and tool face angle, the oriented core sample is restored to its original occurrence in order to determine the geological stability of the oriented core sample and obtain the direction of in-situ stress in the oriented core sample. Using the drilling location as the origin of the spatial coordinates, the spatial positions of the upper and lower ends of the directional core sample are calculated, and spatial modeling is performed in combination with the stratigraphic composition and strike information to obtain the stratigraphic structure model; Based on the included angle between the upper and lower end faces of the directional core sample, determine the next drilling direction and position, and repeat the above steps of obtaining directional core samples, restoring the original occurrence and spatial modeling based on the next drilling direction and position until the three drilling positions that are farthest apart from each other and closest to the upper and lower end faces of the target layer sample are selected to form the target area. Obtain borehole water pressure fracturing test data within the target area, compare and analyze the borehole water pressure fracturing test data with the stratigraphic structure model, and invert the regional stratigraphic strike and geostress direction.

[0005] Furthermore, based on the apex angle, azimuth angle, and tool face angle, the oriented core samples are restored to their original occurrence to determine their geological stability, including: The directional rock core sample was physically reset and its spatial attitude was simulated using a reset device. Based on the apex angle, azimuth angle, and tool face angle, the oriented core samples were restored to their original occurrence. Based on the oriented core samples restored to their original orientation, determine whether there are fractures or fluid infiltration in the sample layer; If the directional core sample is fractured or has fluid seepage, the target area will be changed to obtain a new directional core sample; otherwise, the spatial location of the directional core sample will be calculated.

[0006] Furthermore, the spatial positions of the upper and lower ends of the oriented core sample are calculated, including: The wellhead location is selected as the origin of the coordinate system to establish a three-dimensional coordinate system; Based on the apex angle and drilling distance obtained by the orientation instrument, calculate the horizontal displacement of the orientation instrument in the horizontal direction and the vertical displacement in the vertical direction. The target position coordinates of the orientation instrument are obtained by accumulating and updating the horizontal displacement, vertical displacement and azimuth angle in the three-dimensional coordinate system. By combining the target location coordinates, apex angle, azimuth angle, distance between the orientation instrument and the top end of the core tube, and distance between the top and bottom ends of the core tube sample, the spatial coordinates of the top and bottom ends of the orientation core sample are calculated.

[0007] Furthermore, the spatial coordinates of the upper and lower ends of the oriented core sample were calculated, including: Calculate the coordinates of the upper end of the oriented core sample:

[0008] Calculate the coordinates of the lower end of the oriented core sample:

[0009] in, The target location coordinates, As the vertex, It is the azimuth angle. This represents the straight-line distance between the orientation instrument and the top of the core tube. This represents the distance between the top and bottom ends of the core tube sample.

[0010] Furthermore, spatial modeling is performed by combining stratigraphic composition and strike information to obtain a stratigraphic structure model, including: Merge the parameters of directional core samples of the same type from adjacent borehole segments; By outputting stratigraphic composition and strike information through a neural network, and combining the calculated spatial positions of the upper and lower ends of the directional core sample, a three-dimensional model is created to reconstruct the stratigraphic strike. By combining the stress release direction reconstructed by the field stress sensor patch, the spatial modeling results are converted into a visualized geological structure model.

[0011] Furthermore, based on the included angle between the upper and lower end faces of the directional core sample, the direction and location of the next drilling step are determined, including: Measure the angle between the upper surface of the oriented core sample and the horizontal plane respectively. and the angle between the lower end face and the horizontal plane ; Calculate the absolute value of the angle between the upper and lower end faces. ; The side with the largest included angle is determined as the next drilling direction, and the position of the next drilling segment is determined at a set distance.

[0012] Furthermore, determining the next drilling direction and location based on the included angle between the upper and lower end faces of the directional core sample also includes: By using a flexible scribing head fixed at the end of the inner core tube retainer, the oriented core sample is etched as it enters the inner core tube, so as to form a long groove for orientation reference on the oriented core sample. Based on the position of the long groove on the directional rock core sample and the fixed relative position of the flexible scribing head and the directional instrument, combined with the directional instrument's azimuth data, the angle between the directional instrument's azimuth zero point and the coordinate origin is calculated. The orientation parameters of the core sample relative to the origin are obtained by calculating the angle between the zero point of the orientation instrument and the origin. The direction of the target stratum is then determined by combining the depth and the angle between the upper and lower end faces, which helps to determine the direction of the next drilling.

[0013] Furthermore, borehole hydraulic fracturing test data within the target area are acquired. This data is then compared and analyzed with the formation structure model to invert the regional strata strike and stress direction, including: Acquire hydraulic fracturing pressure data, fracture images from borehole television, and geostress test results from directional core samples at three drilling locations within the target area; By comparing the direction and magnitude of in-situ stress tests at the three drilling locations, stress concentration areas and stable areas can be identified. The results of geostress tests are input into the geomechanical model to simulate the in-situ stress field distribution; The simulated in-situ stress field distribution is compared with actual test data to optimize model parameters, and the regional stratum strike and stress direction are inverted to formulate excavation plans.

[0014] An electronic device includes: a processor; and a memory communicatively connected to the processor; wherein the memory stores a computer program executable by the processor, the computer program being executed by the processor to enable the processor to perform the above-described method for fine characterization of the stress direction in directional drilling.

[0015] A computer-readable storage medium storing computer instructions for causing a computer to perform the above-described method for fine characterization of the direction of directional borehole stress.

[0016] The technical solution of the present invention has at least the following advantages and beneficial effects: This invention enables spatial attitude simulation and physical repositioning of ultra-deep directional rock cores, accurately restoring the original occurrence and stratigraphic strike of the rock samples. Furthermore, by combining multi-segment spatial coordinate calculation and 3D modeling technology, it not only achieves the visualization of complex geological structures but also accurately identifies stress concentration zones and stable zones. This significantly reduces the probability of encountering water inrush or collapse disasters during deep excavation operations and effectively optimizes the model parameters of the in-situ stress field, thereby significantly improving the safety of engineering construction. Attached Figure Description

[0017] Figure 1 A schematic diagram of the orientation parameter model of the orientation instrument provided by the present invention; Figure 2 A schematic diagram of the spatial coordinate parameter model of the directional rock core sample provided by the present invention; Figure 3 A flowchart illustrating the method for fine characterization of the geostress direction in directional drilling provided by the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] It should be noted that the terms "first," "second," etc., in the specification and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used herein can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "including" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to the aforementioned process, method, product, or apparatus.

[0020] This invention provides a method for finely characterizing the geostress direction in directional drilling, aiming to solve the problems of difficulty in achieving accurate three-dimensional spatial repositioning of cores after extraction in traditional deep geological exploration coring operations. This leads to severe loss of information on the original strata strike and geostress direction, and the lack of joint verification of multi-well data, which easily results in misjudgments of strata stability. Based on wireline coring technology and gyro-based inertial navigation inclination measurement technology, this invention achieves efficient and accurate characterization of the geostress field in ultra-deep and complex strata through an innovative core attitude spatial physical repositioning model and a joint three-dimensional inversion algorithm for multi-well parameters, combined with a closed-loop verification mechanism of in-hole hydraulic fracturing testing.

[0021] Example 1 like Figure 3 As shown, the first embodiment of the present invention relates to a method for fine characterization of the stress direction in directional drilling, specifically including the following steps 101 to 105: Step 101: Select a borehole section in the target area and drill down to obtain directional core samples. Based on the inertial navigation and inclination measurement of the drilling gyroscope and the flexible characterization and calibration of the inner tube retainer, obtain the apex angle, azimuth angle and tool face angle of the directional core samples.

[0022] Among them, wireline coring refers to a coring technique that retrieves a core tube containing the rock core directly from inside the drill pipe to the surface using a steel wire rope without extracting the entire drill string. Throughout the drilling workflow, a directional instrument, i.e., a drilling-while-drilling gyroscope inertial navigation system, records the apex angle, azimuth angle, and tool face angle of the current depth in real time to uniquely determine the absolute spatial attitude of the core sample deep underground. For example... Figure 1 The orientation parameter model shown is more clearly defined by selecting the center point of the wellhead's entry point on the surface as the reference origin to establish a three-dimensional rectangular coordinate system. The positive horizontal axis points due north, the positive vertical axis points due east, and the positive vertical axis points vertically downwards towards the Earth's center. Figure 1In the revealed spatial angular relationships, the apex angle is defined as the angle between the longitudinal axis and the vertical axis of the orientation instrument, reflecting the vertical deviation of the borehole; the azimuth angle is defined as the clockwise angle between the projection line of the orientation instrument on the horizontal plane and the transverse axis, determining the absolute orientation of the drilling trajectory on the horizontal plane; and the tool face angle is defined as the relative deflection angle of the orientation instrument's measurement reference zero point on a section perpendicular to the borehole axis. By acquiring and recording these three major angular parameters in real time, the control system can accurately lock the true three-dimensional posture of the orientation core sample at the moment it is peeled from the parent rock in three-dimensional space.

[0023] Step 102: Based on the apex angle, azimuth angle, and tool face angle, the oriented core sample is restored to its original occurrence in order to determine the geological stability of the oriented core sample and obtain the direction of in-situ stress in the oriented core sample.

[0024] The original orientation refers to the natural spatial distribution and stress bearing state of the directional core sample before it is cut by the drill bit. Due to the unavoidable mechanical spin and displacement during the core extraction process, the orientation of the directional core sample retrieved to the ground has been completely altered. This embodiment introduces a multi-degree-of-freedom servo reset device to perform spatial physical reset and orientation simulation of the directional core sample based on the real-time recorded apex angle, azimuth angle, and tool face angle.

[0025] In the specific implementation process, the control unit of the reset device converts the tool face angle into a circumferential rotation compensation command, driving the base tray to rotate the oriented rock core sample in the opposite direction around its own axis by the corresponding degree; it converts the apex angle and azimuth angle into pitch and yaw control commands for the dual-axis gimbal, enabling the oriented rock core sample to accurately reproduce its absolute spatial dip and orientation underground on the operating table. After physical reset, technicians directly conduct geological stability assessments on the restored oriented rock core sample. The geological stability assessment indicators mainly include whether natural fault slip zones are developed in the sample layer, whether there are traces of fluid infiltration and erosion, and the density of the rock mass structure. At the same time, high-sensitivity stress plates are attached to specific locations on the surface of the restored oriented rock core sample, and combined with a high-precision goniometer, the normal dip angle and dip direction of the potential separation surface and slip surface inside the rock mass are directly measured, thereby accurately interpreting the initial in-situ stress release direction indicated by the unloading expansion of the rock mass.

[0026] Step 103: Using the drilling location as the origin of the spatial coordinates, calculate the spatial positions of the upper and lower ends of the directional core sample, and combine the stratigraphic composition and strike information to perform spatial modeling to obtain the stratigraphic structure model.

[0027] In this embodiment, the control system sets the borehole opening point as the origin of the global spatial coordinate system. By performing differential accumulation calculations on the drilling trajectory parameters recorded by the orientation instrument, the absolute three-dimensional coordinates of the directional core sample at a deep underground depth are calculated. Considering that the core tube itself has a fixed geometric length and the relative position of the orientation instrument and the core tube is fixed, the system extends the calculation along the borehole axis to calculate the spatial coordinate points of the top and bottom end faces of the directional core sample. After merging the parameters of directional core samples of the same type from adjacent borehole sections, the system establishes a local spatial coordinate point aggregator.

[0028] After completing the spatial coordinate calculation, the system uses a neural network model to extract depth features from the acquired logging data and core scan images, intelligently outputting the lithological composition ratio and bedding strike information of the current borehole section. The main control chip of the control system fuses multi-source data, including the spatial coordinates of the upper and lower ends of the directional core sample, the stratigraphic composition and strike information output by the neural network, and the stress release direction obtained in step 102, and imports it into the 3D modeling engine to perform spatial topology reconstruction. The 3D modeling engine constructs an intuitive and visual 3D stratigraphic structure model through point cloud interpolation and surface fitting algorithms, realistically restoring the undulating shape and stress field gradient distribution of the underground rock strata.

[0029] Step 104: Based on the included angle between the upper and lower end faces of the directional core sample, determine the next drilling direction and position, and repeat the above steps to select the three drilling positions that are farthest apart from each other and closest to the upper and lower end faces of the target layer sample to form the target area.

[0030] Specifically, the rock strata in deep formations exhibit local folding and abrupt dip angle changes. This embodiment introduces a target tracking strategy based on the gradient of the end-face angle. When measuring the angle, a semi-compound drill string is used, with the core tube inside being a semi-compound tube. The core tube is placed on a horizontal surface to stabilize the core sample. The semi-compound tube is then opened, and other materials are removed, leaving only the target sample. Subsequently, a protractor is used to repeatedly measure the angle between the upper end face of the target sample and the horizontal plane, and the average value is recorded as . The same method was used to measure the angle between the lower end face of the target sample and the horizontal plane multiple times, and the average value was recorded as . The system calculates the absolute difference between the included angles of the upper and lower end faces. This absolute difference directly reflects the degree of bending or tilting of the strata at the current location. Based on the principle of continuous stress transmission in geomechanics, the location of the greatest change in stratum dip angle often points to the core area where tectonic stress is most concentrated or where geological evolution is most active.

[0031] The control system automatically plans the side with the most drastic angle change as the target azimuth for the next exploration borehole, and locks the location of the new borehole section within a range of 0.5 to 2 km along that direction. Through three iterations of coring and attitude restoration calculations, the system intelligently selects three drilling locations within the vast exploration block that are farthest apart on the horizontal projection plane to ensure exploration coverage, and closest in absolute distance between the upper and lower surfaces of the target stratigraphic sample to ensure stratigraphic consistency. The geometric connection of these three drilling locations constructs a target area in geographic space with high representativeness and data closed-loop verification capabilities.

[0032] Step 105: Obtain borehole water pressure fracturing test data within the target area, compare and analyze the borehole water pressure fracturing test data with the formation structure model, and invert the regional stratum strike and geostress direction.

[0033] In this embodiment, after the target area is constructed, the system controls a high-pressure pump unit to conduct in-hole hydraulic fracturing tests at three open-hole sections at different drilling locations. The in-hole hydraulic fracturing test involves injecting high-pressure fluid into isolated sections until the borehole wall rock undergoes tensile fracturing, obtaining the fracturing pressure and closure pressure. After acquiring the in-hole hydraulic fracturing test data, the system combines the actual fracture images obtained from the ultrasonic borehole television probe lowered into the borehole with the geostress test results from the directional core to extract the precise fracture orientation and dip angle.

[0034] The central processing unit (CPU) compares the direction and magnitude of in-situ stress tests at three drilling locations to identify stress concentration zones and stable zones. The measured in-situ stress test results are then input into a geomechanical model to simulate the in-situ stress field distribution. A full-matrix comparative analysis is performed between the simulated in-situ stress field distribution data and the actual borehole hydraulic fracturing test data. Error backpropagation is used to optimize the geomechanical model parameters, ultimately outputting a globally optimal regional stratigraphic strike and three-dimensional in-situ stress field direction distribution map. This data is then used to formulate precise and safe underground engineering excavation plans.

[0035] Example 2 The second embodiment of the present invention provides a method for fine characterization of the geostress direction of directional drilling. This embodiment is a supplement to the first embodiment described above. The supplement is that the step in step 102, which restores the directional core sample to its original occurrence based on the apex angle, azimuth angle and tool face angle, is described in detail to determine the geological stability of the directional core sample.

[0036] The specific steps in this embodiment include: The directional rock core sample was physically reset and its spatial attitude was simulated using a reset device. Based on the apex angle, azimuth angle, and tool face angle, the oriented core samples were restored to their original occurrence. Based on the oriented core samples restored to their original orientation, determine whether there are fractures or fluid infiltration in the sample layer; If the directional core sample is fractured or has fluid seepage, the target area should be changed to obtain a new directional core sample; If it does not exist, then proceed with the step of calculating the spatial location of the oriented core sample.

[0037] Specifically, deep rock masses contain numerous microfractures and structural joint surfaces. If the target exploration area contains active fault fracture zones or strong underground confined water seepage channels, blind excavation will face extremely serious risks of well flooding or large-scale roof collapse. This embodiment establishes a geological risk pre-screening mechanism. After the repositioning device accurately restores the oriented rock core sample to its true dip and azimuth underground, the system uses microscopic detection equipment to directly perform high-precision scanning observation of the sample surface and sections in situ.

[0038] Understandably, if obvious fault zones are observed on the restored directional core sample, or if numerous filling veins or dissolution cavities left by underground fluid migration are detected, the system immediately determines that the geological stability of the block where the current drilling location is located is extremely poor and marks it as an engineering no-go zone. At this time, the central control logic forcibly terminates the subsequent coordinate calculation work for the current block and outputs a scheduling instruction to change the target area and reacquire directional core samples. Only when the restored directional core sample has a dense overall texture, continuous and intact bedding planes, and no physical characteristics of fluid erosion and degradation will the system allow and continue to execute the step of calculating the spatial location of the directional core sample. The above mechanism greatly reduces the high cost losses caused by ineffective exploration and avoids major engineering geological disasters from the source.

[0039] Example 3 The third embodiment of the present invention provides a method for fine characterization of the geostress direction in directional drilling. This embodiment is a supplement to the first embodiment described above. The supplement is that the mathematical analytical steps for calculating the spatial positions of the upper and lower ends of the directional core sample in step 103 are explained.

[0040] The calculation steps in this embodiment specifically include: A three-dimensional coordinate system is established by selecting the wellhead location as the origin, with the horizontal axis pointing due north. Based on the apex angle obtained by the orientation instrument Based on the drilling distance, calculate the horizontal displacement of the orientation instrument in the horizontal direction and the vertical displacement in the vertical direction. ; The target position coordinates of the orientation instrument are obtained by accumulating and updating the horizontal displacement, vertical displacement and azimuth angle in the three-dimensional coordinate system. By combining the target location coordinates, apex angle, azimuth angle, distance between the orientation instrument and the top end of the core tube, and distance between the top and bottom ends of the core tube sample, the spatial coordinates of the top and bottom ends of the orientation core sample are calculated.

[0041] In practice, we assume the horizontal displacement is... Then, based on the derivation of trigonometric functions:

[0042] in, This is the drilling distance. It is the vertex angle.

[0043] This horizontal displacement is further decomposed into mutually perpendicular horizontal and vertical axes. The displacement components on the horizontal axis... and displacement components on the vertical axis The calculation formula is as follows:

[0044]

[0045] in, This is the azimuth angle measured by the orientation instrument.

[0046] Meanwhile, assuming the vertical displacement is The vertical displacement of the orientation instrument in the vertical direction is calculated using trigonometric functions:

[0047] Based on the calculated horizontal displacement components , and vertical displacement The system updates the target position coordinates in a three-dimensional coordinate system. It extracts the previous position coordinates and accumulates the current displacement increment, using the following recursive formula: New target x-coordinate = previous target x-coordinate + Δx New target y-coordinate = previous target y-coordinate + Δy New target z-coordinate = previous target z-coordinate + Δz Based on this, such as Figure 2 The spatial coordinate parameter model of the directional rock core sample shown extends the calculation of the absolute coordinates at both ends of the rock core sample. The aperture point is set as the spatial origin, and the current spatial coordinates of the orientation instrument are set as... The azimuth angle of the orientation instrument is The apex is .like Figure 2 As shown in the calibration relationship, the straight-line distance parameter between the orientation instrument and the upper end of the core tube is: The distance parameter between the upper and lower ends of the sample inside the core tube is: Since the orientation instrument and the core tube are connected as fixed instruments, their spatial orientation axes are considered constant, and the unit vector of this orientation axis is represented as... .

[0048] For the upper part of the core, the distance of its relative extension to the orientation instrument is the distance parameter. At this point, the minute drilling distance is replaced with the distance parameter. The coordinate increments are obtained as follows:

[0049]

[0050] Compare the unit vector increment with the orientation instrument's spatial coordinates Combining these, the three-dimensional absolute coordinates of the upper part of the core are output as follows: .

[0051] For the lower end of the core sample, the total extension distance of its relative orientation instrument is equal to the straight-line distance parameter. Distance parameters to core tube samples The sum of these, at this point the coordinate increment becomes:

[0052]

[0053]

[0054] Similarly, after accumulating the increments, the three-dimensional absolute coordinates of the lower end of the core sample are output at once as follows: .

[0055] This embodiment, through the above-described algebraic spatial geometric model derivation, applies a purely analytical geometric vector translation algorithm throughout, completely eliminating the cumulative error of deep borehole coordinate transformation and ensuring the absolute accuracy of the positional information of each borehole segment in the established three-dimensional geological model.

[0056] Example 4 The fourth embodiment of the present invention provides a method for fine characterization of the geostress direction in directional drilling. This embodiment is a supplement to the first embodiment described above. The supplement is that the core auxiliary orientation and feature binding step added before determining the next drilling direction and position in step 104 is explained.

[0057] Specifically, before determining the next drilling direction and position, this embodiment also includes: By using a flexible scribing head fixed at the end of the inner core tube retainer, the oriented core sample is etched as it enters the inner core tube, so as to form a long groove for orientation reference on the oriented core sample. Based on the position of the long groove on the directional rock core sample and the fixed relative position of the flexible scribing head and the directional instrument, combined with the directional instrument's azimuth data, the angle between the directional instrument's azimuth zero point and the coordinate origin is calculated. The orientation parameters of the core sample relative to the origin are obtained by calculating the angle between the zero point of the orientation instrument and the origin. The direction of the target stratum is then determined by combining the depth and the angle between the upper and lower end faces, which helps to determine the next drilling direction.

[0058] In the specific implementation environment of this embodiment, the deep core sample is highly susceptible to unpredictable circumferential spin at the moment it is cut by the drill bit and pushed into the inner core tube, due to the complex stress release at the bottom of the borehole. If the relative rotation angle at the moment of sample entry into the tube cannot be locked, all inertial navigation attitude data will lose its physical attachment point. To address this, this embodiment uses a high-strength alloy to embed and fix a flexible scribing head on the inner wall of the retaining spring seat at the bottom of the inner core tube. As the drill bit continuously cuts the formation, causing the core sample to continuously flow upward into the inner core tube, the flexible scribing head adheres tightly to the outer cylindrical surface of the core sample and continuously applies mechanical scraping force. The scraping action forcibly etchs a uniformly deep and longitudinally continuous physical groove on the outer surface of the oriented core sample.

[0059] More specifically, during the assembly of the entire coring drill string, the spatial azimuth of the flexible scriber and the sensing reference zero point inside the upper orientation instrument have been strictly fixed and locked relative to each other using a laser alignment device. Once the directional core sample with the long groove is pulled to the surface, the long groove becomes the sole physical key to recording the in-situ orientation underground. The control system uses a 3D scanner to read the absolute physical central angle of the long groove on the circumferential direction of the directional core sample's cross-section. Combined with the pre-calibrated fixed angle compensation value between the flexible scriber and the orientation instrument, and then substituting the azimuth data recorded by the orientation instrument at the moment of coring, it reverse-engineers and accurately calculates the angle between the orientation instrument's azimuth zero point and the global coordinate origin.

[0060] Based on the angle data obtained from the above calculations, the system accurately solves for the direction parameters of the bedding planes and various geological structures within the current directional core sample relative to the external global geodetic coordinate system. Furthermore, by jointly performing matrix calculations with the obtained direction parameters, sample core depth data, and the measured bedding angle parameters of the upper and lower end faces, the system can determine the macroscopic strike and dip pattern of the target strata underground with extremely high accuracy. This provides irrefutable physical positioning support for the system's decision to move the drilling rig to the side with the most drastic angle change. This embodiment cleverly transforms the complex problem of underground spatial attitude transmission into a rigid coupling calculation between physical long groove markings and sensor zero-position data, greatly enhancing the data robustness of the geostress inversion system.

[0061] Example 5 A fifth embodiment of the present invention provides an electronic device including a processor; and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, which are executed by the processor to enable the processor to perform various steps of the fine characterization method for directional drilling stress direction in the above embodiments.

[0062] The memory and processor are connected via a bus. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be further described in this embodiment. Specifically, the processor can be a high-performance field-programmable gate array (FPGA) or a digital signal processing chip to meet the computing power requirements for complex spatial coordinate matrix calculations and three-dimensional geological neural network modeling.

[0063] Example 6 A sixth embodiment of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements any of the above-described method embodiments. The storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0064] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of protection of the patent, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for finely characterizing the direction of in-situ stress in directional drilling, characterized in that, include: In the target area, select a section of borehole to drill and obtain directional core samples. Based on the inertial navigation and tilt measurement of the drilling gyroscope and the flexible characterization and calibration of the inner tube retainer, obtain the apex angle, azimuth angle and tool face angle of the directional core samples. Based on the apex angle, azimuth angle, and tool face angle, the oriented core sample is restored to its original occurrence in order to determine the geological stability of the oriented core sample and obtain the direction of in-situ stress in the oriented core sample. Using the drilling location as the origin of the spatial coordinates, the spatial positions of the upper and lower ends of the directional core sample are calculated, and spatial modeling is performed in combination with the stratigraphic composition and strike information to obtain the stratigraphic structure model; Based on the included angle between the upper and lower end faces of the directional core sample, determine the next drilling direction and position, and repeat the above steps of obtaining directional core samples, restoring the original occurrence and spatial modeling based on the next drilling direction and position until the three drilling positions that are farthest apart from each other and closest to the upper and lower end faces of the target layer sample are selected to form the target area. Obtain borehole water pressure fracturing test data within the target area, compare and analyze the borehole water pressure fracturing test data with the stratigraphic structure model, and invert the regional stratigraphic strike and geostress direction.

2. The method for finely characterizing the geostress direction in directional drilling according to claim 1, characterized in that, Based on the apex angle, azimuth angle, and tool face angle, oriented core samples are restored to their original occurrence to determine their geological stability, including: The directional rock core sample was physically reset and its spatial attitude was simulated using a reset device. Based on the apex angle, azimuth angle, and tool face angle, the oriented core samples were restored to their original occurrence. Based on the oriented core samples restored to their original orientation, determine whether there are fractures or fluid infiltration in the sample layer; If the directional core sample is fractured or has fluid seepage, the target area will be changed to obtain a new directional core sample; otherwise, the spatial location of the directional core sample will be calculated.

3. The method for finely characterizing the geostress direction in directional drilling according to claim 1, characterized in that, Calculate the spatial positions of the upper and lower ends of the oriented core sample, including: The wellhead location is selected as the origin of the coordinate system to establish a three-dimensional coordinate system; Based on the apex angle and drilling distance obtained by the orientation instrument, calculate the horizontal displacement of the orientation instrument in the horizontal direction and the vertical displacement in the vertical direction. The target position coordinates of the orientation instrument are obtained by accumulating and updating the horizontal displacement, vertical displacement and azimuth angle in the three-dimensional coordinate system. By combining the target location coordinates, apex angle, azimuth angle, distance between the orientation instrument and the top end of the core tube, and distance between the top and bottom ends of the core tube sample, the spatial coordinates of the top and bottom ends of the orientation core sample are calculated.

4. The method for finely characterizing the geostress direction in directional drilling according to claim 3, characterized in that, The spatial coordinates of the upper and lower ends of the oriented core sample were calculated, including: Calculate the coordinates of the upper end of the oriented core sample: Calculate the coordinates of the lower end of the oriented core sample: in, The target location coordinates, As the vertex, It is the azimuth angle. This represents the straight-line distance between the orientation instrument and the top of the core tube. This represents the distance between the top and bottom ends of the core tube sample.

5. The method for finely characterizing the direction of in-situ stress in directional drilling according to claim 1, characterized in that, Spatial modeling is performed by combining stratigraphic composition and strike information to obtain a stratigraphic structure model, including: Merge the parameters of directional core samples of the same type from adjacent borehole segments; By outputting stratigraphic composition and strike information through a neural network, and combining the calculated spatial positions of the upper and lower ends of the directional core sample, a three-dimensional model is created to reconstruct the stratigraphic strike. By combining the stress release direction reconstructed by the field stress sensor patch, the spatial modeling results are converted into a visualized geological structure model.

6. The method for finely characterizing the geostress direction in directional drilling according to claim 1, characterized in that, Based on the included angle between the upper and lower end faces of the directional core sample, determine the direction and location of the next drilling pass, including: Measure the angle between the upper surface of the oriented core sample and the horizontal plane respectively. and the angle between the lower end face and the horizontal plane ; Calculate the absolute value of the angle between the upper and lower end faces. ; The side with the largest included angle is determined as the next drilling direction, and the position of the next drilling segment is determined at a set distance.

7. The method for finely characterizing the geostress direction in directional drilling according to claim 6, characterized in that, Based on the included angle between the upper and lower end faces of the directional core sample, the direction and location of the next drilling step are determined, which also includes: By using a flexible scribing head fixed at the end of the inner core tube retainer, the oriented core sample is etched as it enters the inner core tube, so as to form a long groove for orientation reference on the oriented core sample. Based on the position of the long groove on the directional rock core sample and the fixed relative position of the flexible scribing head and the directional instrument, combined with the directional instrument's azimuth data, the angle between the directional instrument's azimuth zero point and the coordinate origin is calculated. The orientation parameters of the core sample relative to the origin are obtained by calculating the angle between the zero point of the orientation instrument and the origin. The direction of the target stratum is then determined by combining the depth and the angle between the upper and lower end faces, which helps to determine the direction of the next drilling step.

8. The method for finely characterizing the geostress direction in directional drilling according to claim 1, characterized in that, Obtain borehole hydraulic fracturing test data within the target area, compare and analyze the borehole hydraulic fracturing test data with the formation structure model, and invert the regional strata strike and in-situ stress direction, including: Acquire hydraulic fracturing pressure data, fracture images from borehole television, and geostress test results from directional core samples at three drilling locations within the target area; By comparing the direction and magnitude of in-situ stress tests at the three drilling locations, stress concentration areas and stable areas can be identified. The results of geostress tests are input into the geomechanical model to simulate the in-situ stress field distribution; The simulated in-situ stress field distribution is compared with actual test data to optimize model parameters, and the regional stratum strike and stress direction are inverted to formulate excavation plans.

9. An electronic device, characterized in that, include: processor; as well as The memory is communicatively connected to the processor; wherein, The memory stores a computer program that can be executed by the processor to enable the processor to perform a fine characterization method for the geostress direction of directional drilling as described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the method for fine characterization of the geostress direction in directional drilling as described in any one of claims 1-8.

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